Coreopsis

As currently understood Coreopsis is a genus of ca. 35 species. Most are native to North America (some extending to tropical America). Species of Coreopsis from the Old World tropics, especially those from tropical Africa, in fact belong to Bidens (Mabberley 2008). Cosmos and some species of Bidens are obviously closely related with Coreopsis and generic limits have long been obscure. Most species have showy, often bright yellow flowers and some are popular as garden ornamentals. Jäger & al. (2008) provide an extensive account of the genus in cultivation in Central Europe.

1. Annual. Ligules yellow, often with a brownish-purplish blotch at base. Tubular florets with 4 lobes === 2. Coreopsis tinctoria

1. Perennial. Ligules entirely yellow. Tubular florets with 5 lobes === 2

2. Leaves divided in linear to filiform segments. Involucral bracts 6-7 mm long. Plant glabrous === 3. C. verticillata

2. Leaves entire or with few lateral lobes, segments never linear or filiform. Involucral bracts 8-12 mm long. Plant usually sparsely hairy === 1. C. lanceolata


Literature:

Crawford D.J. & Mort M.E. (2005) Phylogeny of eastern North American Coreopsis (Asteraceae-Coreopsideae): insights from nuclear and plastid sequences, and comments on character evolution. Amer. J. Bot. 92: 330-336.

Dress W.J. (1965) Notes on the cultivated Compositae, 8. Thelesperma, Bidens, Coreopsis. Baileya 13: 20-42.

Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.

Kim S.C., Crawford D.J., Mesfin Tadesse, Berbee M., Ganders F.R., Pirseyedi M. & Esselman E.J. (1999) ITS sequences and phylogenetic relationships in Bidens and Coreopsis (Asteraceae). Syst. Bot. 24(3): 480-493.

Knees S.G. (2000) Coreopsis. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 6. Cambridge University Press, Cambridge: 657-658.

Mabberley D.J. (2008) Mabberley’s plant-book (3th ed.). Cambridge University Press, Cambridge: XVIII + 1021 p.

Mesfin Tadesse, Crawford D.J. & Kim S.C. (2001) A cladistic analysis of morphological features in Bidens L. and Coreopsis L. (Asteraceae-Heliantheae) with notes on generic delimitation and systematics. Biol. Skr. 54: 85-102.

Sherff E.E. (1936) Revision of the genus Coreopsis. Publ. Field Mus. Nat. Hist., Bot. Ser. 11: 475 p.

Strother J.L. (2006) Coreopsis. In: Flora of North America Editorial Committee (eds.), Flora of North America, vol. 21. Oxford University Press, New York-Oxford: 185-198

Taxonomic name: 
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith